Sequence Analysis Of Y-STR DYS709,DYS710 And DYS722 Loci And Their Genetic Polymorphism Among Shanxi Han Population

Objective To analysis the sequence characteristics and the genetic polymorphism of the three Y-STR loci(DYS709,DYS710 and DYS722) and obtain the allele and haplotype frequencies of them, then discuss the possibility of applying them to forensic science by investigating 120 unrelated Han males of the three Y-STR loci in Shanxi population, to meet the need of more genetic markers in forensic practice and genetic analysis.Methods The DNA were extracted by phenol/chloroform method, choosed three Y-STR loci DYS709,DYS710 and DYS722,and amplified with PCR,the products were analysised by agarose gel electrophoresis and nondenaturing polyacrylamide gel electrophoresis. Analysis the genetic polymorphism of 120 unrelated Han males in Shanxi population,20 female and 15 family were also carried out. Different male animals and different tissues (including blood, muscle, et al) of one corpse were analyzed.Results The results show that the DYS709 locus consists of repeats of a core sequence(ttct),five alleles were found,they are named 21,22,23,24,25respectively with the allele frequency of 0.1833,0.2750,0.2167,0.2083,0.1333 and the gene diversity is 0.8021,the discriminating power and excluding probability of paternity are the same. The DYS710 locus contains three copies of a sequence motif, this motif has the following modular structure: (gaaa)14-18(gaga)6-8ga(gaaa)10-14, where the value of (14～18 +6～8 +10～14 +1) ranges between 34 and 38 among different individuals,with the frequency of 0.1667,0.2167,0.3167,0.1917,0.1083 and the discriminating power is 0.7899. The results show that the DYS722 locus consists of repeats of a core sequence (gaaa), five alleles were found, they are named 19,20,21,22,23 respectively with the allele frequency of 0.1667,0.2500,0.2667,0.2083,0.1250 and the gene diversity is 0.8089,the discriminating power and excluding probability of paternity are the same. Among 120 Shanxi Han males, 77 different haplotypes of these three loci were identified. Of these, 48 occurred only once, with a frequency of 0.0083, and the most common haplotype occurred at a frequency of 0.3333. This system has a haplotype diversity (HD) of 0.9995 and the discriminating power (DP) of 0.9995. PCR products were not found in female DNA. The analysis of 15 father/son pairs has detected no mutation at the three locus. Different tissue from one corpse also has the same allele in the three new Y-STR loci, shows that the three Y-STR loci have a good tissue oneness.Conclusion These results indicate that the DYS709,DYS710 and DYS722 loci are high genetic polymorphic, the haplotype diversity shows good discriminating power and high excluding chance of paternity.They are to be useful genetic markers in forensic science and human evolution studies.